Process of forming roads and the like



Aug. 21, 1928. 1,681,353

M. LEVY PROCESS OF FORMING ROADS AND THE LIKE Origifial Filed Nov. 2. 1922 Patented Aug. 21, 1928.

UNITED STATES 1,6 PATENT OFFICE.

MABCELLEVY, or onmrvaswrrznnrlann, ASSIGNOR 'ro monon." FABnIQUE DE rnonurrs oneamcuns s. A, or GENEVA, SWITZERLAND.

'rnocnss or FORMING moans m 1.11m.

' Original application filed November 2, 1922, Serial No. 593,651, and in jGreat. Britain January 3, 1922. Divided and this application filed July, 1024.- 'lerlal Io. 727,574.

- In my application Serial No. 598,651 filed 2nd November, 1922, I have dealt with the manufacture of concretes from a special hard pitch and a graded filling.

5 The object of the resent invention is to provide a 'met-hod'o forming a paving or roadway employing such concrete.

The aforesaid concrete has nothing in commonwith tar products which are used for coating or pavlng roads, pavements or the like because these products must usually be comparatively soft and-elastic. The new 4 concrete. cannot be so em loyed satisfactorily because it may have a liability to crack under the impact of steel tyres or horses hoofs.

I havefound, however, that this pitch concrete may be successfully used in the manufacture of road surfaces and the like if'it is covered by a thin coating of some more plastic body which deadens the shocks, such a body for example as asphalt.

Thus, the pitch concrete as indicated in application No. 598,651 may be used on roads.

or pavements in place of cement concretes 2 which in certaincases are coated with a layer of asphalt.

The reason why the pitch concrete used in the present invention may'replace cement concrctes for the purpose specified is that it has mechanical properties substantially similar to cement concrete, that is to say it is hard, and nonlastic, has a crushing strength of at least a out 4,000 to 5,000 lbs. per square inch, has a tensile strength when tested in the manner of testing cement con cretes, that is to say without thelarge particles of the aggregate of at least about 4:00 to 500 lbs. per'square inch, and has a sub.- stantial resistance to abrasion or wear.

invention, I find that only a thin layer of asphalt is necessary. The asphalt or like lastic body is not relied on to give stren th ut merely to assist in minimizing the e ect of shocks. It amalgamates with or welds solidly to the pitch concrete base and there is little tendency for it to flow from the centre to the sides of the road, the required covering being quite thin.

This invention therefore consists in a method of manufacturing a road, pavement or the like which comprises theprovision of apitch concrete made accordingto copending application No. 598,651 and a relatively Y get-her while being heated With such pitch concrete according to the thin coating of a resilient or elastic substance, for example,"asphalt. Tar ora mix ;tion. of .a road constructed according to one form of the present invention.

In the drawing, the roadway is indicated by the letter 0;. Above this, there is a stone foundation (2 carrying a mixture, marked 0, I

of hard pitch, broken-stone, sand and 'p0W-- der, reference to which is given in 'more'de- .tilll below, the whole being coveredby an asphalt surface (1. j

Such a paving may for example be con structed in the following nianner: The new concrete is first poured on to the surface to be covered and then a resilient and elastic matenal is poured on to the concrete sub-structure.

Paving slabs may also be formed from the new concrete, of which the surface is coated with a layer of resilient and elastic material.

- Such an example will now be given:

The following substances are mixed to- 450 kgs. gas itch, mineral oil pitch or any other pltch of inferior and: cheap quality,

which remains hard in water at C. (In.

the mass has set and while still hot it is coated with a layer of asphalt 5-20 mm. thick. The road'or paving obtained in this manner forms after setting a single block as the asphalt'layer effectively and solidly ad- 'heres to the sub-structure of pitch concrete.-

As will be seen from the foregoing the present process differs from the known processes by reason of the fact that a solid and strong concrete is first produced, which however is too hard to withstand without damage the shocks'on pavements or roads due to traflic and horses hoofs, for which reason a layer of asphalt is poured thereon so that both layers intimatel combine with one another and form a soli entirety. If a piece of the new.concrete'coated with asphalt is broken off with a hammer, then the'asphalt layer remains firmly attached to the concrete and the fracture is similar to that which would be formed were the whole mass entirel homogeneous.

In order to facilitate the combination of an old pitch concrete with a new one the surface of the old concrete may be coated with a varnish or simply with tar or a thin layer of soft asphalt may be poured between the old and the new concrete while the latter is still hot and viscous. This can be done in the following manner The new still viscous and soft layer of concrete is se arated from the old layer by a trowel an asphalt is poured into the small intervening space. Iuthis manner an effective combination is obtained between the two layers while the connecting layer is at the same time also elastic.

The new concrete covered witha plastic layer may also be used for indoor floors.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. The method of laying a roadway which name to this specification.

comprises forming a substratum of a pitch concrete which is hard, non-plastic and has a crushing strength of at least about 4,000 to 5,000 lbs. per square inch and tensile strength when the large aggregate is not present of'about 400 to 500 lbs. per square inch and substantially retains these properties under temperature conditions of use by mixing said pitch concrete by incorporating into hard pitch under the action of heat a graded aggre te and filling material, laying this mixe pitch concrete as a substratum and covering this substratum with a thin coating of a plastic substance which solidly adheres thereto.

2. A method as claimed in claim 1, in which the plastic substance is plastic asphaltum-like matter. I

3. Roadway blocks made of pitch concrete having a crushing strength of at least about 4,000 to 5,000 lbs. per square inch and tensile strength when the large ag egate is not present of about 400 to 500 s. per square inch and substantially retains these properties under temperature conditions of use, containing a graded filling material and coated at least on one surface with a thin coating of a plastic asphaltum-like substance which solidly adheres thereto.

In testimony whereof I have signed my MARGEL LEVY. 

